Load weighing systems, and, in particular, weighing systems for vehicles such as logging trucks and trailers, typically use a plurality of load cell assemblies to monitor the weight added to the trucks and trailers. Load cell assemblies usually include a machined steel block that is supported between load-carrying members, such as log supports, and mounting members, such as truck or trailer frames. In each block there are formed slots which serve to direct the load to a predetermined area.
FIG. 1 illustrates a prior art load cell block 10 supported between a load-carrying member 12 and a mounting block 24, which is welded to a mounting member 14 attached to a trailer frame 16. The load cell block 10 has formed therein first and second end slots 18, which serve to direct the load applied by the load-carrying member 12, attached to a top beam 20, to a central portion 22, and thence to bottom beams 23, which support the central portion 22 above the mounting blocks 24. The amount of stress in the bottom beams 23 is measured by strain gauges (not shown) located along the lower surface 25 of the bottom beams 23. While this type of load cell block has proved to be highly accurate and reliable, it has been subject to a number of malfunctions resulting from cracks 28 that form at the terminal end 30 of the slots 18 when a severe load is applied, as indicated by the arrows 32.
It has been found that the stress cracks result from the formation of score marks in the terminal end 30 of the slots 18 when the slots 18 are formed by milling. In particular, the milling machine leaves lateral machining marks that serve as stress concentrations at the junction of the central body and the upper and lower beams. Thus, it is desirable to eliminate these machining marks to reduce the formation of the stress cracks. It has further been found that bending load forces can be directed to predetermined locations for strain gauges by forming lateral grooves at the predetermined locations on the block.